The objectives of these studies are: to investigate the relationships of biologic, genetic, medical, and environmental factors in the parents--including events in pregnancy, labor, and delivery--to the normal and abnormal development of the offspring; to investigate the relationships of these factors to pregnancy loss in the form of early fetal death, perinatal mortality, infant and childhood mortality, and to incidence of congenital anomalies; to provide detailed growth curves for children suitable for the study of differences in growth rate according to the above factors; to provide estimates of illness and injury rates in infants and children; to investigate the relationships of physical and mental development in early childhood to those during the period of puberty and adolescence. The investigations are conducted on members of the Kaiser Foundation Health Plan--a prepaid medical health plan--who reside in the San Francisco East Bay area. Information was obtained from the gravida early in pregnancy on a number of medical, biologic, and environmental factors. Blood typing in seven systems was obtained on the gravida, her husband, and the cord blood of the infant. Samples of serum were frozen for serologic analysis. The method of study is longitudinal for both mother and child. In addition to information obtained specifically for the studies, the medical records for the gravida and child provided information on illnesses, as well as on prescribed drugs. These data form the base for investigations of physiologic and pathologic changes during pregnancy and for evaluations of teratogenic effects of prenatal diseases and prescribed drugs. Special developmental examinations were given to 5-year-old and 10-year-old children, providing extensive information on physical and mental developmental characteristics.